EP2470765A1

EP2470765A1 - Cylinder block with injection and ejection piston

Info

Publication number: EP2470765A1
Application number: EP10751781A
Authority: EP
Inventors: Jesper Soberg
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-08-24
Filing date: 2010-08-24
Publication date: 2012-07-04
Also published as: WO2011023195A1; DK201070370A

Abstract

The present invention concerns a cylinder block for a combustion engine with a second piston having an injection stroke by displacement of a second working face towards a top position for suction through a cylinder port of at least one reactant to a reaction chamber, and that the second piston has an ejection stroke by displacement of the second working face towards a bottom position for exhaust through an exhaust port of a reaction product from a reaction chamber.

Description

Cylinder Block with Injection and Ejection Piston

Field of the Invention

The present invention concerns a cylinder block for a combustion engine, including a cylinder housing with a cylinder chamber having a first end and a second end, and which has a cylinder wall; a first piston with a first working face which is displaceable in the first end of the cylinder chamber between a first extreme position which is a top dead centre, TDC, and a second extreme position which is a bottom dead centre, BDC, the first piston interacting with a machine operating outside the cylinder housing.

Moreover, there is provided a second piston with a second working face which is displaceable in the second end of the cylinder chamber between a first extreme position, which is a top position, and a second extreme position, which is a bottom position, and where the two working faces are facing each other, and where the two working faces together with the cylinder wall define a reaction chamber.

There is provided a cylinder port, an exhaust port and optionally an igniter provided with connection to the reaction chamber. The special feature is that second piston is provided an injection stroke by displacement of a second working face towards the top position for suction of at least one reactant through the cylinder port to the reaction chamber, and that the second piston is provided an ejection stroke by displacement of the second working face towards a bottom position for exhaust through the exhaust port of a reaction product from the reaction chamber.

Background of the Invention

It is inherent in industrialisation that man has efficiently achieved to convert stored energy to useful work. Typically, a machine is powered by the work produced by a motor in which is stored energy in a fuel by combustion is converted to heat and pressure, which in a chamber interact with a piston which is then displaced, thereby performing work. Combustion engines in which a piston in connection with combustion is displaced in a cylinder chamber, thereby performing work, have been known for a long time. The predominant and previously produced combustion engines operate by two cycles, four cycles or six cycles, as the piston operates between a top dead centre TDC and a bottom dead centre BDC.

The four-cycle engine is characterised by having

- a suction stroke in which air and fuel are received in the combustion chamber;

- a compression stroke in which air and fuel are compressed and ignited;

- a work stroke in which the fuel is combusted, and the hot combustion gases press the piston downwards; and

- an exhaust stroke in which the combustion product is ejected from the combustion chamber.

In the exhaust stroke, the movement of the piston depends on energy from other side, which most often is from other pistons in other cylinder chambers.

The two-cycle engine is characterised by having

- a compression stroke in which air and fuel are compressed and ignited;

- a work stroke in which the piston is pressed downwards by the hot combustion gases, and where suction and exhaust occurs with the piston at the bottom dead centre. The piston may here be said also to function as a valve as the piston is closing and opening, respectively, a port in the cylinder wall.

Compared with the four-cycle engine, the extra cycles in the six-cycle engine are used for utilising the excess heat from the combustion, as vapour is formed which cools the cylinder and provides an extra work stroke as well. In US patent no. 6,612,273, a double-piston combustion and compression chamber is described with basis in a two-cycle engine. The patent discloses a primary piston and a secondary piston as an exhaust and a suction piston that may travel at different speeds in the compression chamber. The description in the patent, which is available to the public, may be regarded as state of the art.

The invention is characterised in that the secondary piston divides the compression and combustion chamber into two parts: A first part which is a mixing chamber having a one-way cylinder port for air and an injector for introducing fuel. A second part which is a compression and combustion chamber having a one-way exhaust port.

In order to transfer the mixture of air and fuel from the mixture chamber to the compression and combustion chamber, the secondary piston is semi-permeable and provided with passages with valves that allow passage in one direction, but which are pressure-tight in the opposite direction.

Object of the Invention

It is the object of the present invention to indicate a technical device which in a simple way provides a reaction chamber with variable volume.

It is thus the object of the present invention to indicate a technical device which in a simple way provides for use of different fuels in a combustion engine, and which not the least provides for efficient cleaning or scavenging of the combustion chamber.

A further object, but not exclusively, and otherwise generally in connection with combustion chambers where the pressure after combustion is substantially close to atmospheric pressure, is to enable performing full scavenging of a combustion chamber in e.g. a free-piston engine, but also in more traditional types of engines.

Furthermore, it is an object of the invention to reduce and simplify existing cylinder blocks which have one or frequently more mechanical valves that are to be adjusted and synchronized accurately in order to provide a proper mixture of fuel and air in the combustion chamber. In this connection is to be mentioned the need for further technical devices in order to make the valves operate. A further object is to provide a technical device which in a simple way lets a combustion chamber be filled with fuel and additionally be emptied of combustion products independently of the position of the working piston. Thereby, different fuels may be used and the best basis for the actual combustion is created. In this way is furthermore achieved an optimal working stroke with most efficiently converts the stored energy in the fuel into work, and the number of cycles in an engine may be reduced to consist exclusively of cycles required for performing a work in a machine, whereby a more efficient engine with a cleaner combustion is obtained.

Description of the Invention

The primary object is fulfilled according to the present invention by a cylinder block for a combustion engine, including a cylinder housing with a cylinder chamber having a first end and a second end, and which has a cylinder wall; a first piston with a first working face which is displaceable in the first end of the cylinder chamber between a first extreme position which is a top dead centre, TDC, and a second extreme position which is a bottom dead centre, BDC, the first piston interacting with a machine operating outside the cylinder housing. There is provided a second piston with a second working face which is displaceable in the second end of the cylinder chamber between a first extreme position, which is a top position, and a second extreme position, which is a bottom position, and where the two working faces are facing each other, and where the two working faces together with the cylinder wall define a reaction chamber. There is furthermore provided a cylinder port, an exhaust port and optionally an igniter which is provided with connection to the reaction chamber. The characterising feature of the invention is that the second piston is provided an injection stroke by displacement of the second working face towards the top position for suction of at least one reactant through a cylinder port to the reaction chamber, and that the second piston is provided an ejection stroke by displacement of the second working face towards a bottom position for exhaust through the exhaust port of a reaction product from the reaction chamber. Hereby is achieved that the second working face of the second piston is displaceable in the reaction chamber in relation to the first working face of the first piston, and that a volume is defined which is delimited by the two working faces and the cylinder wall. According to the invention, thereby is provided a simple technical device by which the volume of the reaction chamber is variable. In connection with emptying, this volume may ideally be zero, whereby the reaction chamber is emptied of reaction products and possible residual reactants from the reaction.

From the ideal situation where the said volume is zero, the volume with expand and reactants will be sucked into the volume through the cylinder port as the injection stroke is performed. As the volume expands, the said reaction chamber functions as a mixing chamber for the reactants.

If the second working face is moved sufficiently slowly and evenly, and if the cylinder port is of a certain size and without edges, the reactants will fill the chamber as a mass that follows the second working face.

If the second working face is introduced relatively fast and with irregular speed, the reactants will whirl around in the reaction chamber and thereby be distributed in the chamber.

If edges are provided in the cylinder port, or if edges are provided at the transition between the reaction chamber and the cylinder port, turbulence will be produced in the chamber and the reactants will whirl around the reaction chamber and thereby be distributed in the chamber.

During and possibly after the reaction, which exerts a work pressure on the first piston face, thereby bringing the first piston to work, the first piston will perform a work stroke and the volume will expand again. Ideally, the volume defined by the two working surfaces and the cylinder wall is at maximum when the ejection stroke is commenced, and the volume is to be regarded as a reaction chamber in which reaction products and possible residual reactants are present. With the exhaust port disposed at the first end of the cylinder chamber, and with the first piston at a position forming connection between the exhaust port and the reaction chamber, and as the second working surface begins its travel against the first working surface, the ejection stroke commences, pressing or pushing reaction products and/or residual reactants out of the exhaust port.

There may be provided a number of exhaust ports and cylinder ports with connection to the reaction chamber. Ideally, the ejection stroke will start at maximum volume which is the volume where the first piston is at BDC, and the other piston is at the top position, and the ejection stroke will be finished when the volume is zero, in which case the reaction chamber is completely emptied. Several designations of the first piston with the first working face may be associated with the function of the element. In the preferred embodiment, it is termed an ejection and injection piston; however, a spraying piston for a reaction chamber is also an adequate term for the ability of the piston to efficiently and simply empty the reaction chamber and to provide an almost ideal filling of the reaction chamber.

Immediately after the injection stroke, the preferred position of the first working piston will be such that the face opposite the second working face is resting, supported by or bearing on a surface which is fixed relative to the cylinder chamber. The mentioned opposite face may be termed a rest face, a support face or a contact face which is complementary to the shape of the cylinder surface finishing the cylinder end.

Ideally, immediately after the injection stroke the first piston will initiate a compression of the reactants. It is presupposed that the second working face is made pressure-tight relative to the cylinder wall. Compression of the reactants may be effected with the intention of self-ignition, or there may be provided an igniter which is typically a spark igniter in the form of a spark plug. There may be cases where the volume of the chamber during the compression advantageously is varied by use of the first as well as the second working face.

Thereby, during the reaction itself the second working face can be regarded as part of the reaction chamber, and the first piston will not perform any work during the reaction itself.

Valve devices are provided in connection with the cylinder port and the exhaust port, where the valve devices control the full or partial opening and closing of the cylinder port and the exhaust port, respectively.

A valve for the cylinder port interacts with the second piston via a connection such that the cylinder port is open during the injection stroke. A valve for the exhaust port interacts with the second piston via a connection such that the exhaust port is open during the ejection stroke.

The valve for the cylinder port interacts with the first piston via a connection such that the cylinder port is closed during at least part of the travel of the first piston from TDC to BDC.

The valve for the cylinder port interacts with the first piston via a connection such that the cylinder port is closed during at least part of the travel of the first piston from BDC to TDC.

The valve for the exhaust port interacts with the first piston via a connection such that the exhaust port is closed during at least part of the travel of the first piston from TDC to BDC. The valve for the exhaust port interacts with the first piston via a connection such that the exhaust port is closed during at least part of the travel of the first piston from BDC to TDC. In an alternative embodiment, the valve for the cylinder port and the valve for the exhaust port are physically interconnected.

The invention finds application for different reactants and is particularly suited when changing between these without needing extensive adjustments and adaptations.

The reactants will typically be fuels combined with associated oxidants. Of fuels can be mentioned petroleum-based fuels, such as petrol, CNG (compressed natural gas), LPG (fluid propane gas), diesel, methanol, or biologically based fuel/fuels, such as bio-ethanol, bio-methanol, bio-ethylene, biogas, nitromethane, or by using coal-based fuels. Moreover, hydrogen will be an ideal fuel since the combustion is very clean and yields almost no other combustion products other than water.

More exotic fuels like nitromethane and DME (dimethyl-ether) may be applied.

Oxidants will typically be oxygen in various mixtures or bonds. Oxygen in atmospheric air will be the most natural.

Reactants may also belong to the class of metals like e.g. aluminium, magnesium, iron and boron, just to mention some mono-component and not only poly-component reactants.

Whether the reactants mainly develop heat by the reaction, the reaction chamber substantially being a combustion chamber, or mainly result in an explosive reaction, the reaction chamber substantially being an explosion chamber, is in principle without significance to the invention.

The choice of material for the working pistons and the cylinder wall is, however, to be adapted with appropriate parameter intervals that fulfil the requirement that the reactions do not degrade the material or react with it. Also, the material may be selected such that appropriate heat conduction is achieved, primarily away from the reaction chamber. The invention is very well suited in connection with so-called free piston engines.

According to a further embodiment, the cylinder block according to the invention is peculiar in that the second working face is unbroken. Hereby is meant that the second working face does not have one or more passages through which reactants or reaction products may pass, either both ways or just one way. The present piston differs substantially from the prior art thereby, and the unbroken second face ensures that the second piston is functioning as injection piston and ejection piston. In addition, the unbroken face will, provided the face is pressure-tight displaceable in the cylinder chamber, cause the chamber between the first working face and the second working face also to be delimited by the cylinder wall and to be one and the same chamber regardless of performing an injection stroke or an ejection stroke. The second working face will typically have a shape which is complementary to the first working face, and one or both working faces will have a cross-sectional profile which is complementary to the cross-sectional profile of the cylinder chamber, where both cross-sections are perpendicular to the passage of the cylinder chamber. The reaction chamber is thereby delimited unambiguously, though the chamber volume is variable, and the reaction chamber is unambiguously communicating with the cylinder port and the exhaust port.

Ih an alternative embodiment, the second working face is freely displaceable in the cylinder chamber without the second working face being in contact with the cylinder wall.

According to a further embodiment, the cylinder block according to the invention is peculiar in that on the second piston and opposite the second working face, a shaft acting through a passage in the cylinder housing is provided, the end of which shaft interacting with an actuator outside the cylinder chamber. Hereby is provided a device such that the travel of the second working piston may be controlled.

It is to be noted that the passage for the shaft is pressure-tight as e.g. sealing rings are provided in the passage.

In the preferred embodiment, the shaft is provided at the centre of the second piston, and the shaft and the second piston are provided rotationally symmetric. However, there is nothing to hinder that the shaft and the second piston may be separated, as they are made with screw thread or other jointing for mounting with the second piston. The second piston may thereby be of one material and the shaft of a different material which e.g. is suited for conducting heat away. According to a further embodiment, the cylinder block according to the invention is peculiar in that the actuator consists of at least one first arrangement of magnets with at least one magnet mounted on the shaft, the first arrangement of magnets interacting with at least one second arrangement of magnets comprising at least one magnet. The injection stroke and the ejection stroke may thereby be activated by the forces that may be produced between the magnets.

In a preferred embodiment, the first arrangement of magnets comprises permanent magnets which are mounted on the shaft such that the north and south poles are oriented in longitudinal direction of the shaft. The second arrangement of magnets consists of two sets of electromagnets, the south and north poles of which also being oriented in longitudinal direction of the shaft and disposed in a holder which is fixed in relation to the cylinder chamber. One set of electromagnets is placed in the holder such that they interact most powerfully with the permanent magnets when the second working face is at the top position, though without the two magnet arrangements coming into physical contact. The other set of electromagnets is placed in the holder such that they interact most powerfully with the permanent magnets when the second working face is at the bottom position, though without the two magnet arrangements coming into physical contact. The shaft with the first magnet arrangement is freely displaceable between the two sets of electromagnets such that the second working face can be moved between the top position and the bottom position. The two sets of electromagnets are activated by the ejection stroke by a controlled current provided such that the first set of the electromagnets repel the permanent magnets on the shaft and such that the second set of electromagnets attract the permanent magnets. By the injection stroke is provided a current running in opposite direction relative to that by the ejection stroke. Thereby, the directions of repelling and attracting magnetic forces are reversed, and the second working face performs the injection stroke.

The finishing of the described injection stroke occurs naturally in that the second piston finds rest against the top of the cylinder chamber. Also, the finishing of the ejection stroke will be defined by the contact of the second working surface to first working surface, or by the shaft being designed with a projection encountering an edge. Even though the described embodiment is ideal, there is nothing in the invention to prevent the actuator with magnet arrangement from being controlled more precisely by applying a controller in connection with the power supply for the two sets of electromagnets. The position of the second working face may thereby be controlled and further optimised for improved suction and improved exhaust. An obvious configuration will be to reverse the current in the set of electromagnets that are immediately receiving the permanent magnet arrangement, whereby the actuator is braked.

There is nothing to prevent the permanent magnets and the electromagnets from being interchanged as well as it may be envisaged that only electromagnets are used or that electromagnets interact with ferromagnetic material fitted on the shaft. The proposed permanent magnets may in principle be of any type, as their magnetic properties are wanted to be retained, why it may be advantageous to insulate them thermally from the shaft and make them with a surface that is less receptive to heat radiation and radiating heat to a higher degree. Outward facing surfaces are silvered in the first instance, but may be provided with a single or multilayered thermal barrier coating made of a ceramic material.

According to a further embodiment, the cylinder block according to the invention is peculiar in that the actuator operates in a vacuum chamber which is optionally connected with a vacuum pump. The air resistance around the actuator is thereby reduced and its action is facilitated, thereby making the second working face operate faster and more precisely.

The inner side of the vacuum chamber has a surface which is more receptive to heat, and an outer side which is more outwardly radiating, such that heat is conducted from the interior of the chamber and in the first instance is dissipated by heat radiation.

The inner side may thus be provided with a single-layer or multi-layer thermal barrier coating made of e.g. a ceramic material for efficient heat conduction towards the outer side of the chamber.

The outer side of the vacuum chamber may, however, be connected to a cooling arrangement which may consist of a radiator grille or be actively air- or water-cooled. The vacuum may also be a gas provided for heat conduction, hi this case, the vacuum pump is substituted by a circulation pump which, if necessary, may interact with a heat exchanger.

According to a further embodiment, the cylinder block according to the invention is peculiar in that the actuator is a pneumatic device.

The preferred embodiment includes a pressure-tight chamber which is divided into two chambers, an upper and a lower, by a piston head which in the first instance is provided with sealing rings. At the upper end, an upper channel is provided, and at the lower end a lower channel. If the pressure is increased in the upper chamber and the pressure is lowered in the lower chamber, the piston head, which is mounted on the shaft which in turn is connected with the second piston, will be pressed downwards and the second piston will perform the ejection stroke. If the pressure is lowered in the upper chamber and the pressure is increased in the lower chamber, the second piston will perform the injection stroke.

The pneumatic actuator may in principle operate at any position that provides the second working face to be located between the top position and the bottom position.

The design of the pneumatic actuator allows for efficient heat conduction.

According to a further embodiment, the cylinder block according to the invention is peculiar in that the actuator is a mechanical device controlling the travel of the second working piston in the reaction chamber.

In the primary embodiment, a cylindric roller is provided at the free end of the shaft and rotatably mounted on the shaft. The roller interacts as cam guide follower with a cam as the roller runs in its cam guide. The cam is rotatably mounted on a camshaft, and the rotation is performed by a motor provided for it. The shape of the cam guide is adapted such that a 360° rotation results in the second working face being displaced from the top position to the bottom position and back again to the top position. The shaft is presupposed to have a linear guide that collect the forces normal to the longitudinal direction of the shaft.

In some cases, the cam guide can be designed to perform adapted injection strokes and ejection strokes, respectively, as the adaptation is effected by the cam guide being designed with an arbitrary however adjusted form of guiding the second piston. According to a further embodiment, the cylinder block according to the invention is peculiar in that on the actuator there is a mechanical coordination mechanically interacting with the first piston. In an optimised and special embodiment, the cam guide shaft is provided with a first roller which via a belt is connected with a second roller mounted on a crankshaft directly following the movement of the first piston. In this case, the second working surface is moved - and thereby the injection stroke and the ejection stroke - in direct dependence on the movement of the first working face.

The first and second rollers may have a circular shape, an elliptic shape or a more arbitrary shape as the belt can be adapted from having a permanent periphery to being elastic. Shapes of the first and second roller that are different from circular shape and made phase shifted, provide a variable speed of the movement of the second working piston.

According to a further embodiment, the cylinder block according to the invention is peculiar in that there is provided at least one pressure equalisation duct connecting a rear chamber with the space outside the cylinder housing.

As the second working face of the second piston is advantageously pressure-tight displaceable in the cylinder chamber, at the side opposite the second working face and the rear chamber thus defined a subpressure will arise by the ejection stroke and an overpressure by the injection stroke. The subpressure and the overpressure are equalised by the pressure equalisation duct.

More pressure equalisation ducts may be provided, e.g. equidistantly around the cylinder housing.

According to a further embodiment, the cylinder block according to the invention is peculiar in that at the same end as the second end of the cylinder chamber, the cylinder housing has a mountable cylinder top in which the passage and optionally a pressure equalisation duct are provided.

By cylinder top is meant a top containing the described second working piston, the shaft, the said actuators and possible adjacent standard components.

As described, by dismounting the cylinder top access will be provided to the reaction chamber in a simple way and the second piston will be exposed for immediate repair, replacement or cleaning as well.

According to a further embodiment, the cylinder block according to the invention is peculiar in that a controller with connection to at least one sensor determining the position of the first piston is provided in connection with the actuator. By position determination is meant in the first instance the position of the first working surface relative to TDC and BDC, which e.g. can be in degrees between 0 and 360, but also other relative or absolute linear dimensions.

According to a further embodiment, the cylinder block according to the invention is peculiar in that a controller with connection to at least one sensor determining the position of the first working piston is provided in connection with the actuator.

By position determination is meant in the first instance the position of the first working surface relative to TDC and BDC, which e.g. can be in degrees between 0 and 360, but also other relative or absolute linear dimensions.

By the controller, the injection stroke and the ejection stroke may be controlled in relation to the strokes of the first working piston. The controller may contain a number of standard programs, procedures, sequences for a number of reactants and combinations of reactants. Similarly, the controllers may contain a number of programs, procedures, sequences of a number of operation conditions which do not exclusively comprise resetting, start, various runs, stop, maintenance and tests. This provided under a number of different conditions, externally and internally and in immediate vicinity of the cylinder block, as e.g. temperature, air humidity, oxygen concentration in the air.

Description of the Drawing

The invention will now be explained more closely with reference to the accompanying drawing, wherein:

Fig. 1 shows the cylinder block with the first piston and the second piston with the first piston in TDC;

Fig. 2 shows the cylinder block with combustion in the reaction chamber;

Fig. 3 shows the cylinder block with termination of combustion in the reaction chamber and with the first piston on its way towards BDC;

Fig. 4 shows the cylinder block with the first piston in BDC and with the second piston during the ejection stroke activated by an actuator consisting of arrangements of magnets;

Fig. 5 shows the cylinder block with the second piston during the injection stroke activated by an actuator consisting of arrangements of magnets;

Fig. 6 shows the cylinder block with the first piston on its way from BDC to TDC; Fig. 7 shows the cylinder block with the second piston during the ejection stroke activated by a pneumatic actuator;

Fig. 8 shows the cylinder block with the second piston during the ejection stroke activated by a mechanical actuator shown as a cam guide arrangement; and Fig. 9 shows the cylinder block with the second piston during the ejection stroke activated by a mechanical actuator interacting with the first piston. Detailed Description of Embodiments of the Invention

The present invention will be described in the following, as the elements below with references form part of the invention.

In the explanation of the Figures, identical or corresponding elements will be provided with the same designations in different Figures. No explanation of all elements will be given in connection with each single Figure/embodiment.

In the following, Fig. 1 to Fig. 6 will contain the same elements but in different strokes. Figs. 7 to 9 will focus on different embodiments. Fig. 1 shows a cylinder block 10 with a combustion engine 11 having a cylinder housing 12 with a cylinder chamber 13 having a first end 20 and a second end 21. The cylinder chamber 13 has a cylinder wall 22. In the cylinder chamber 13 and close to the cylinder wall 22, there is provided a first piston 23 with a first working face 24 which in shape is complementary to the cross-section of the cylinder chamber 13 so that the first working face 24 of the first piston 23 may operate in the cylinder chamber 13 between a top dead centre denoted TDC 25, and a bottom dead centre denoted BDC 26.

The first piston 23 is shown here interacting with a machine 27 which is not comprised by the invention and is only included for exemplifying that work is performed. Furthermore, Fig. 1 shows a second piston 30 with a second working face 31 which will be described together with other elements in the following, as the other elements are concurrently introduced for the sake of clarity. hi continuation of Fig. 1, Fig. 2 shows a cylinder block 10 as in Fig. 1 where the second working face 31 has a top position 32 which is defined in that the second piston 30 is located at its extreme position with contact close to TDC 25. The second working face 31 furthermore has a bottom position 33 which is defined in that the second working face 31 is in contact with the first working face 24. The bottom position 33 is thus variable in its position in the cylinder chamber 13 and varies depending on the position of the first working face 24 in the cylinder chamber 13.

The first working face 24, the second working face 31 and the cylinder wall 22 delimit a volume which is a reaction chamber 34 which is thus having a variable volume depending on the positions of the first working face 24 and the second working face 31.

There is provided a cylinder port 35 and an exhaust port 36 at the first end 20 of the cylinder chamber 13 at such position that the cylinder port 35 and the exhaust port 36 with the first piston 23 at BDC 26 have free access to the reaction chamber 34. The cylinder port 35 and the exhaust port 36 are here shown closed, but in drawings below they will be shown open. hi connection with the reaction chamber 34, an igniter 37 may optionally be provided as shown in Fig. 2.

Fig. 3 shows in continuation of Figs. 1 and 2 the cylinder block 10 at the finish of the combustion in the reaction chamber 34, and with the first piston 23 on its way to BDC 26, in which situation the reaction chamber is preferably filled with a reaction product 38. The second piston 30 is located at the top position 32, and the cylinder port 35 and the exhaust port 36 are still closed.

Fig. 4 shows in continuation of Figs. 1-3 the cylinder block 10 with the first piston at BDC 26 and with the second piston 30 during an ejection stroke 40 caused by an actuator 41, here consisting of a first arrangement of magnets 42 and a second arrangement of magnets 44 which are both provided in a chamber, which is here a vacuum chamber 45 connected to a vacuum pump 46. The first arrangement of magnets is provided on a shaft 43 connected with the second piston 30.

As the second piston 30 is moved from its top position 32 against its bottom position, an exhaust 47 of reaction products 38 is performed out through the exhaust port 36, which is now open via a valve for the exhaust port 48. The shaft 43 runs in a passage 49 provided in the cylinder housing 12 and which is ideally pressure-tight and with a linear guide in parallel with the movement of the second working face 31 in the cylinder chamber 13.

Fig. 5 shows in continuation of Figs. 1-4 the cylinder block 10 with the second piston 30 during an injection stroke 50 activated by the actuator 41, which here consists of the first arrangement of magnets 42 provided on the shaft 43 with connection to the second piston 30. The first arrangement of magnets interacts with the second arrangement of magnets 44 for performing the injection stroke 50. During the injection stroke 50, the second piston 30 is moved from its top position 33 towards its top position 32, and thereby the injection stroke 50 causes suction 51 of at least one reactant 52 through the cylinder port 35 which here is open via a valve for the cylinder port 53 , thus filling the reaction chamber 34.

For equalising pressure by the ejection stroke 40 and the injection stroke 50, a pressure equalisation duct 54, which connects a rear chamber 55 with the space 56 outside the cylinder housing 12, is provided in the cylinder housing 12.

Fig. 6 shows in continuation of Figs. 1-5 the cylinder block 10 with the second piston 30 at its top position 32 and the first piston 23 on its way from BDC 26 to TDC 25, whereby the volume of the reaction chamber 34 is reduced and the reactants 52 are compressed.

I the following Figs. 7 to 9 and with reference to Figs. 1-6, the cylinder block 10 is shown with different actuators 41 for the second piston 30. Common to Figs. 7 to 9 is the fact that the stroke of the second piston 23 is connected with the ejection stroke 40. The principle of the injection stroke 50 and the other positions is, however, identical with those introduced by Figs. 1 to 6.

Fig. 7 shows with reference to the Figs. 1 to 6 the cylinder block 10 with the second piston 30 during the ejection stroke activated by a pneumatic device 70 which is provided above the cylinder housing 12. The pneumatic device 70 includes a pressure- tight chamber housing 71 which by a piston head 72 is divided into an upper chamber 73 and a lower chamber 74. In connection with the upper chamber 73, an upper channel 75 is provided, and in connection with the lower chamber 74, a lower channel 76 is provided, where the said ducts 75, 76 are used for applying pressure changes in the upper chamber 73 and the lower chamber 74, as overpressure in the upper chamber 73 and subpressure in the lower chamber 74 will cause the piston head 72, which via the shaft 43 is connected to the second piston 30, to provide the ejection stroke 40. The injection stroke 50 is provided by forming an subpressure in the upper chamber 73 and an overpressure in the lower chamber 74.

Fig. 8 shows with reference to Figs. 1 to 6 the cylinder block 10 with the second piston 30 activated by a mechanical device 80 as a cam guide arrangement 81, where a cam 82 rotates about a camshaft 83 and interacts with a cam follower 84 which is linked to the shaft 43 which in turn is connected with the second piston 30. The cam

82 has a cam guide, the shape of which being defined by a cam guide profile 85. By a cam rotation 86 of 360°, the second piston 30 will be displaced in the cylinder chamber 13 between the top position 32 and the bottom position 33 and back, thereby performing the ejection stroke 40 and the injection stroke 50. In the cylinder chamber

13, the shaft 43 has a linear guide 87 which is pressure- tight.

Fig. 9 shows with reference to Figs. 1-6 and 8 the cylinder block 10 with a second piston 30 activated by a mechanical coordination 90 in that the mechanical device 80 interacts with the first piston 23. The mechanical coordination 90 is provided in that a first roller 91 is mounted on the camshaft 83, turning in phase with the cam 82, that a second roller 92 is mounted on a crankshaft 93 rotating by means of the connection to the first piston 23 via a piston rod 94. The first roller 91 is connected to the second roller 92 via a belt 95. The first roller 91 has a first roller profile 96, and the second roller 92 has a second roller profile 97 such that displacement of the first piston 23 between TDC 25 and BDC 26 and back results in a phase shifted displacement of the second piston 30 between the bottom position 33 and the top position 32. In the shown position, the second piston 30 performs the ejection stroke 40.

Claims

1. A cylinder block (10) for a combustion engine (11), including - a cylinder housing (12) with a cylinder chamber (13) having a first end (20) and a second end (21), and which has a cylinder wall (22);- a first piston (23) with a first working face (24) which is displaceable in the first end (20) of the cylinder chamber (13) between a first extreme position which is a top dead centre, TDC (25), and a second extreme position which is a bottom dead centre, BDC (26), which first piston (23) interacts with a machine (27) operating outside the cylinder housing (12);

- a second piston (30) with a second working face (31) which is displaceable in the second end (21) of the cylinder chamber (13) between a first extreme position, which is a top position (32), and a second extreme position, which is a bottom position (33), and where the two working faces (24, 31) are facing each other, and where the two working faces (24, 31) together with the cylinder wall (22) define a reaction chamber (34);

- a cylinder port (35);- an exhaust port (36);- optionally an igniter (37) provided with connection to the reaction chamber (34);characterised in that

- the second piston (30) is provided an injection stroke (50) by displacing the second working face (31) towards the top position (32) for suction (51) through the cylinder port (35) of at least one reactant (52) to the reaction chamber (34); and- the second piston (30) is provided an ejection stroke (40) by displacing the second working face (31) towards the bottom position (33) for exhaust (47) through the exhaust port (36) of a reaction product (38) from the reaction chamber (34).

2. Cylinder block (10) according to claim 1, characterised in that the second working face (31) is unbroken.

3. Cylinder block (10) according to claim 1 or 2, characterised in that on the second piston (30) and opposite the second working face (31), a shaft (43) acting through a passage (49) is provided, the end of which shaft (43) interacting with an actuator (41) outside the cylinder chamber (13).

4. Cylinder block (10) according to claim 3, characterised in that the actuator (41) consists of at least one first arrangement of magnets (42) with at least one magnet mounted on the shaft (43), the first arrangement of magnets (42) interacting with at least one second arrangement of magnets (44) comprising at least one magnet.

5. Cylinder block (10) according to claim 3, characterised in that the actuator (41) operates in a vacuum chamber (45) which is optionally connected with a vacuum pump (46).

6. Cylinder block (10) according to claim 3, characterised in that the actuator (41) is a pneumatic device (70).

7. Cylinder block (10) according to claim 3, characterised in that the actuator (41) is a mechanical device (80).

8. Cylinder block (10) according to claim 3, characterised in that a mechanical coordination (90) interacting mechanically with the first piston (23) is provided on the actuator (41).

9. Cylinder block (10) according to any of claims 1 to 8, characterised in that at least one pressure equalization duct (54) connecting a rear chamber (55) with the space (56) outside the cylinder housing (12) is provided.

10. Cylinder block (10) according to any of claims 3 to 9, characterised in that at the same end as the second end (21) of the cylinder chamber (12), the cylinder housing (12) is provided with a mountable cylinder top containing the actuator (21).